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+/* Copyright (C) 1996 Free Software Foundation, Inc.
+
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+/* Return the address of the last occurrance of a given character
+ within a null-terminated string, or null if it is not found.
+
+ This is generally scheduled for the EV5 (got to look out for my own
+ interests :-), but with EV4 needs in mind. There are, in fact, fewer
+ stalls on the EV4 than there are on the EV5.
+*/
+
+#include <sysdep.h>
+
+ .set noreorder
+ .set noat
+
+ENTRY(strrchr)
+ .prologue 0
+
+ zapnot a1, 1, a1 # e0 : zero extend our test character
+ mov zero, t6 # .. e1 : t6 is last match aligned addr
+ sll a1, 8, t5 # e0 : replicate our test character
+ mov zero, t7 # .. e1 : t7 is last match byte compare mask
+ or t5, a1, a1 # e0 :
+ ldq_u t0, 0(a0) # .. e1 : load first quadword
+ sll a1, 16, t5 # e0 :
+ andnot a0, 7, v0 # .. e1 : align source addr
+ or t5, a1, a1 # e0 :
+ lda t4, -1 # .. e1 : build garbage mask
+ sll a1, 32, t5 # e0 :
+ cmpbge zero, t0, t1 # .. e1 : bits set iff byte == zero
+ mskqh t4, a0, t4 # e0 :
+ or t5, a1, a1 # .. e1 : character replication complete
+ xor t0, a1, t2 # e0 : make bytes == c zero
+ cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage
+ cmpbge zero, t2, t3 # e0 : bits set iff byte == c
+ andnot t1, t4, t1 # .. e1 : clear garbage from null test
+ andnot t3, t4, t3 # e0 : clear garbage from char test
+ bne t1, $eos # .. e1 : did we already hit the terminator?
+
+ /* Character search main loop */
+$loop:
+ ldq t0, 8(v0) # e0 : load next quadword
+ cmovne t3, v0, t6 # .. e1 : save previous comparisons match
+ cmovne t3, t3, t7 # e0 :
+ addq v0, 8, v0 # .. e1 :
+ xor t0, a1, t2 # e0 :
+ cmpbge zero, t0, t1 # .. e1 : bits set iff byte == zero
+ cmpbge zero, t2, t3 # e0 : bits set iff byte == c
+ beq t1, $loop # .. e1 : if we havnt seen a null, loop
+
+ /* Mask out character matches after terminator */
+$eos:
+ negq t1, t4 # e0 : isolate first null byte match
+ and t1, t4, t4 # e1 :
+ subq t4, 1, t5 # e0 : build a mask of the bytes upto...
+ or t4, t5, t4 # e1 : ... and including the null
+
+ and t3, t4, t3 # e0 : mask out char matches after null
+ cmovne t3, t3, t7 # .. e1 : save it, if match found
+ cmovne t3, v0, t6 # e0 :
+
+ /* Locate the address of the last matched character */
+
+ /* Retain the early exit for the ev4 -- the ev5 mispredict penalty
+ is 5 cycles -- the same as just falling through. */
+ beq t7, $retnull # .. e1 :
+
+ and t7, 0xf0, t2 # e0 : binary search for the high bit set
+ cmovne t2, t2, t7 # .. e1 (zdb)
+ cmovne t2, 4, t2 # e0 :
+ and t7, 0xcc, t1 # .. e1 :
+ cmovne t1, t1, t7 # e0 :
+ cmovne t1, 2, t1 # .. e1 :
+ and t7, 0xaa, t0 # e0 :
+ cmovne t0, 1, t0 # .. e1 (zdb)
+ addq t2, t1, t1 # e0 :
+ addq t6, t0, v0 # .. e1 : add our aligned base ptr to the mix
+ addq v0, t1, v0 # e0 :
+ ret # .. e1 :
+
+$retnull:
+ mov zero, v0 # e0 :
+ ret # .. e1 :
+
+ END(strrchr)
+
+weak_alias (strrchr, rindex)